Electron Configuration Practice Worksheet In the space below, write the unabbreviated electron configurations of the following elements: 1) sodium ________________________________________________ 2) iron ________________________________________________ 3) bromine ________________________________________________ 4) barium ________________________________________________ 5) neptunium ________________________________________________ In the space below, write the abbreviated electron configurations of the following elements: 6) cobalt ________________________________________________ 7) silver ________________________________________________ 8) tellurium ________________________________________________ 9) radium ________________________________________________ 10) lawrencium ________________________________________________ Determine what elements are denoted by the following electron configurations: 11) 1s22s22p63s23p4 ____________________ 12) 1s22s22p63s23p64s23d104p65s1 ____________________ 13) [Kr] 5s24d105p3 ____________________ 14) [Xe] 6s24f145d6 ____________________ 15) [Rn] 7s25f11 ____________________ Determine which of the following electron configurations are not valid: 16) 1s22s22p63s23p64s24d104p5 ____________________ 17) 1s22s22p63s33d5 ____________________ 18) [Ra] 7s25f8 ____________________ 19) [Kr] 5s24d105p5 ____________________ 20) [Xe] ____________________ Need homework help? Visit www.chemfiesta.com ! Electron Configurations - Solutions Note: The electron configurations in this worksheet assume that lanthanum (La) is the first element in the 4f block and that actinium (Ac) is the first element in the 5f block. If your periodic table doesn’t agree with this, your answers for elements near the f-orbitals may be slightly different. 1) sodium 1s22s22p63s1 2) iron 1s22s22p63s23p64s23d6 3) bromine 1s22s22p63s23p64s23d104p5 4) barium 1s22s22p63s23p64s23d104p65s24d105p66s2 5) neptunium 1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p67s25f5 6) cobalt [Ar] 4s23d7 7) silver [Kr] 5s24d9 8) tellurium [Kr] 5s24d105p4 9) radium [Rn] 7s2 10) lawrencium [Rn] 7s25f146d1 11) 1s22s22p63s23p4 sulfur 12) 1s22s22p63s23p64s23d104p65s1 rubidium 13) [Kr] 5s24d105p3 antimony 14) [Xe] 6s24f145d6 osmium 15) [Rn] 7s25f11 einsteinium 16) 1s22s22p63s23p64s24d104p5 not valid (take a look at “4d”) 17) 1s22s22p63s33d5 not valid (3p comes after 3s) 18) [Ra] 7s25f8 not valid (radium isn’t a noble gas) 19) [Kr] 5s24d105p5 valid 20) [Xe] not valid (an element can’t be its own electron configuration) Need homework help? Visit www.chemfiesta.com !